EFFECT OF COENZYME Q 10 SUPPLEMENTATION IN THE RAT MODEL OF ADJUVANT ARTHRITIS

Adjuvant arthritis (AA) is a model of chronic inflammation induced by Mycobacterium butyricum and characterized by similar pathophysiological and pathobiochemical changes as rheumatoid arthritis (RA) in humans. In this study the antirheumatic activity of coenzyme Q 10 supplementation was tested not only as to its capability to suppress the inflammation edema of the hind paw and to improve the body weight of the arthritic animals, but also to improve so important biochemical parameters as markers of inflammation and oxidative stress, and of mitochondrial bioenergetics. Despite the unfavorable effects on the rheumatic processes observed by monitoring biometric parameters (hind paw volume, relative body weight, relative weight of spleen), a significant protective effect was observed on the level of mitochondrial energetic and antioxidant disbalance. This finding speaks in favor of CoQ10 supplementation in rheumatic patients, presumably as combinatory therapy with classical antirheumatics, e.g. NSAIDs.


INTRODUCTION
Adjuvant arthritis (AA) is a model of chronic inflammation induced by Mycobacterium butyricum and characterized by similar pathophysiological and pathobiochemical changes as rheumatoid arthritis (RA) in humans.Oxidative stress, involved in the etiopathogenesis of RA, may participate in disturbances of mitochondrial ultrastructure and function, leading to decreased efficiency and atrophy of the skeletal muscle.Previously 1 we found stimulation of skeletal muscle mitochondrial function and coenzyme Q 9 (CoQ 9 ) concentration in AA rats.Compounds with antirheumatic properties reversed these changes.Based on known antioxidant and bioenergetic properties, a beneficial effect of coenzyme Q 10 was proposed in the pathogenesis of arthritis.In this study, the antirheumatic activity of coenzyme Q 10 supplementation was tested not only as to its capability to suppress the inflammation edema of the hind paw and to improve the body weight of the arthritic animals, but also to improve so important biochemical parameters as markers of inflammation and oxidative stress, and of mitochondrial bioenergetics.

MATERIAL AND METHODS
Male Lewis rats were divided into four groups, each of 7-9 animals: C -controls, Q 10 -control rats supplemented with CoQ 10 during 28 days in daily dose 20 mg/kg body weight by intragastric tube, AA -adjuvant arthritis induced intradermally by Mycobacterium butyricum in incomplete Freund's adjuvant, AA + Q 10 -AA rats supplemented with CoQ 10 .All biometric and biochemical parameters monitored were measured on the 28 th experimental day when the animals were sacrificed.For lipid peroxidation assessment, the plasmatic levels of thiobarbituric acid reactive substances (TBARS) were determined spectrophotometrically 2 .The plasmatic levels of carbonyls (CBN) 3,4 , the plasmatic activity of N-acetyl-β-D-glucosaminidase (NAGA) (ref. 5) and gamma-glutamyl transpeptidase (GGTP) (ref. 6) were also assessed spectrophotometrically.Mitochondria of the skeletal muscle were isolated by differential centrifugation, respiratory chain function was measured using Clark oxygen electrode 7 .Concentrations of CoQ 9 , CoQ 10 and α-tocopherol (α-toc) in plasma and skeletal muscle mitochondria were determined by HPLC method 8,9 .Further the increase of the hind paw volume, decrease of the relative body weight and changes in the relative weight of the spleen were monitored.
The data were expressed as mean + standard error of mean (SEM).Statistical evaluation was performed using unpaired Student's t-test.For declaration of significance the two-tailed P value was taken into consideration.

RESULTS AND DISCUSSION
Adjuvant arthritis significantly induced lipoperoxidation in plasma (Table 1), significantly stimulated CoQ 9 and α-tocopherol concentration in skeletal muscle mitochondria and slightly stimulated mitochondrial function  2).Due to the rheumatic processes, the plasmatic activity of NAGA and the level of plasmatic carbonyls were slightly increased.From the therapeutic aspect, the effect of supplementation with CoQ 10 was positive in the case K. Bauerova, J. Kucharska, D. Mihalova, J. Navarova, A. Gvozdjakova, Z. Sumbalova of plasma carbonyls and disputable for the activity of NAGA (Table 1).The effect of CoQ 10 supplementation on GGTP activity in skeletal muscle was without significance (Table 2).
As seen from the Table 3, all biometric parameters were unfavorably affected due to the arthritic processes.The relative body weight was unaffected by the compound tested.The other parameters were higher, which could reflect indirectly a stimulation of inflammation processes.In conclusion, despite these unfavorable effects on the rheumatic processes, a significant protective effect was observed on the level of mitochondrial antioxidant disbalance.This finding may favor CoQ 10 supplementation in rheumatic patients, presumably as a combinatory therapy with classical antirheumatics, e.g.NSAIDs.

Table 1 .
Parameters monitored in plasma: concentrations of antioxidants, thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CBN), activity of NAGA

Table 2 .
Parameters monitored in skeletal muscle: mitochondrial function and antioxidants concentrations,

Table 3 .
Biometric parameters monitored: increase of hind paw volume (HPV), decrease of relative body weight (RBW), changes in relative weight of the spleen (RWS)

Table 2 )
. Supplementation with CoQ 10 in AA rats restored α-tocopherol concentration in plasma but did not suppress lipoperoxidation (Table1).Increased concentration of CoQ 9 in skeletal muscle mitochondria in AA rats was significantly reduced by CoQ 10 supplementation.Activity of Complex I of the respiratory chain was decreased, function of Complex II was slightly stimulated (Table